Assessing response in bone metastases in prostate cancer with diffusion weighted MRI

Abstract

Mean ADC is not an appropriate measure of response in bone metastases. The heterogeneity of changes in ADC is likely to be related to the composition of bone marrow with changes that have opposing effects on ADC.

Apparent Diffusion Coefficient Maps Integrated in Whole-Body MRI Examination for the Evaluation of Tumor Response to Chemotherapy in Patients with Multiple Myeloma

“…Additionally, signal intensity of T1 and STIRT2 images were not useful for monitoring response to chemotherapy because most of the treatment-induced changes seen on MRI were not specific (2,5). Even in the present study, the DWI was also evaluated in bone metastases secondary to prostate cancer (27). After chemotherapy, ADC values decreased in some lesions and increased in others, both in responders and nonresponders.…”

Whole-Body Diffusion-weighted MR Imaging in Cancer: Current Status and Research Directions

“…The ability to confi dently detect small increases in ADC may not be useful with regard to personalized medicine for patients with bone metastases. This is because increases in ADC may be seen in responders and nonresponders; the important point to remember is that ADC increases in nonresponders may be modest, whereas ADC changes in responders are usually larger ( 139 ).…”

“…Bone metastases that do not respond to cytotoxic therapy can show a slight increase ( 139 ), stability, or a decrease in ADC. The biophysical causes and limits for these ADC changes and the corresponding signal intensity appearances defi nitely require clarifi cation for clinical deployment and drug development.…”

MRI for Response Assessment In Oncologic Bone Marrow Lesions

“…DWI has been shown able to detect ADC increase within prostate cancer metastases treated with antiandrogen therapy as early as one month after treatment initiation Koh et al 2007;Reischauer et al 2010). The effectiveness of ADC monitoring to predict the response of bone metastases to therapy is however controversial (Messiou et al 2011). The interpretation of changes in ADC values is indeed complex, mainly due to tumor and response heterogeneity.…”